Mathematics problem 52 When a steel ball with a diameter of 2 cm rolls on the table, how many cm is the center of the ball from the table

Mathematics problem 52 When a steel ball with a diameter of 2 cm rolls on the table, how many cm is the center of the ball from the table

It's a radius, one centimeter

In the first quarter of 2006, a total of 760 TV sets were sold in a shopping mall. The ratio of sales in January to march was 3:4, and that in January to February was 6:5. What was the ratio of sales in the first three months? How many TV sets were sold in each of the three months?

In the first quarter of 2006, a total of 760 TV sets were sold in a shopping mall. The ratio of sales in January to march was 3:4, and that in January to February was 6:5. What was the ratio of sales in the first three months? How many TV sets were sold in each of the three months?
January: March = 3:4 = 6:8
January: February = 6:5
January: February: March = 6:5:8
January: 760 * 6 / (6 + 5 + 8) = 240
February: 760 * 5 / 19 = 200
March: 760 * 8 / 19 = 320

There are 52 people who buy cola, buy 5 bottles and get one free. How many bottles do you need to buy?
There are 52 people who buy Coke, buy 5 bottles get 1 free
How many bottles do you need to buy?
I know the answer is 42 bottles
Want to know how to do this kind of topic
In addition to the answer, is there any easy to understand way to solve this kind of problem

42 bottles
5*8=40
8 bottles for free
42-40=2
8+2=10
Two more bottles
42 + 8 + 2 = 52 bottles